The rational use of environmental regulation tools has become an important means by which to improve the efficiency of carbon emissions. Different types of environmental regulations and their combinations have different impacts on carbon emission efficiency. In order to determine the environmental regulation configurations that may achieve high carbon emission efficiency or lead to low carbon emission efficiency, we constructed an analytical framework of connections between environmental regulation configurations and carbon emission efficiency. Moreover, 30 Chinese provinces from the period covering 2016 to 2019 were selected as research cases. In addition, the super slacks-based measure of efficiency (SE-SBM) model was applied to evaluate carbon emission efficiency. Finally, the fuzzy-set qualitative comparative analysis (fsQCA) method was employed to analyze the impact of different environmental regulation configurations on carbon emission efficiency. The results showed that the carbon emission efficiency of various regions of China is generally low (with most regions not having reached an effective level) and that there are large regional differences. We found that there are four environmental regulation configurations that can achieve high carbon emission efficiency and two environmental regulation configurations that lead to low carbon emission efficiency. Based on these configurations, we draw three conclusions: (1) There are three paths to achieving high carbon emission efficiency: one that values command-and-control environmental regulation but disfavors market-incentive environmental regulation, another that combines command-and-control environmental regulation with market-incentive environmental regulation, and a third that couples command-and-control environmental regulation with voluntary environmental regulation. (2) Two paths that may lead to low carbon emission efficiency were established: excessive penalties and the lack of specific measures. (3) In some conditions, environmental governance investment and fiscal expenditure could be substituted for each other; environmental protection administrative penalties and pollution charges are synchronized; environmental governance investment in the promotion of carbon emission efficiency is indispensable. Policies and suggestions on how the government can use environmental regulation tools to improve carbon emission efficiency are proposed from a general coordinative perspective in the final section of this paper.

This study aims to analyze the nonlinear relationship between environmental regulation and carbon emission efficiency and provide scientific reference for achieving the goal for carbon neutrality at a lower cost. Taking 30 provinces in China, using dual carbon policy as the research objects, the slacks-based measure–Malmquist–Luenberger (SBM–ML) index method was used to measure the carbon emission efficiency from 2009 to 2019 and a panel threshold regression model was established to explore the nonlinear effects of environmental regulation and carbon emission efficiency in each province. The results show that: (1) during the sample period, there is geographical variability in CEE, with the eastern coastal provinces having the highest CEE, followed by the central and western provinces, and the resource-dependent provinces having the lowest CEE and their energy consumption and utilization efficiency being significantly lower than other provinces; (2) when the energy consumption intensity is used as a threshold variable, the relationship between environmental regulation and carbon emission rate is an inverted “U” shape; and (3) when green technology innovation is used as a threshold variable, the relationship between environmental regulation and carbon emission rate is a “U” shape. This study provides a new perspective for improving carbon emission efficiency.

Energy security and ecological and environmental security are some of the most basic and important preconditions for national development, and ecological compensation is an important institutional guarantee for construction of China’s ecological civilization. The Chinese government has always made it clear that it will “step up efforts to protect the ecosystem” and establish market-based and diversified ecological compensation mechanisms. However, the existing system and mechanism design of ecological environment protection has been unable to meet the needs of economic and social development in the new era. On the basis of the psychological account theory and prospect theory, this paper constructed an evaluation system of strategic mineral resources exploitation and ecological environmental protection effects in Western China using the VIKOR-AISM model. In this paper, the VIKOR-AISM model comprehensively considers the maximization of group utility and minimization of individual regrets, and conducts a cluster analysis based on the compromise value Q and its inflection $k$. The comprehensive ranking changes of evaluation subjects under different decision preferences and hesitation interval measures were studied according to the antagonist hierarchy topology. The research results provide decision-making support for China to formulate ecological compensation policies in line with regional characteristics.

The realization of the “double-carbon” goal will contribute to the high-quality and sustainable development of China’s economy and society, while the improvement of carbon emission efficiency in Chinese provinces will lay a solid foundation for the realization of the “double-carbon” goal. In this paper, 30 Chinese provinces are selected as research cases. MatLab software is applied to build the slacks-based measure Malmquist-Luenberger (SBM-ML) model to measure carbon efficiency. By the analysis of their carbon efficiency with the fuzzy qualitative comparative analysis (fsQCA) method, this paper aims to find new ways to improve carbon emission efficiency. Among the data of all the provinces and municipalities, there are only four are greater than 1, revealing much room for improvement in Chinese carbon emission efficiency. The carbon emission efficiency of each province and municipality is synergistically influenced by five elements: environmental regulation, urbanization rate, marketization level, consumer price index, and government environmental expenditure. Different configurations of the five elements constitute four feasible ways to improve carbon emission efficiency. The total consistency level of 0.822277 indicates that the four paths are sufficient conditions for achieving high carbon emission efficiency. The conclusions of this paper are not only helpful in accurately grasping the carbon emission efficiency in Chinese provinces but also provide theoretical support and practical guidance for improving the carbon emission efficiency in China.